A morphological and morphometric study of the prosimian lung: The lesser bushbaby Galago senegalensis

The lung of the lesser bushbaby (Galago senegalensis) has been investigated morphologically and morphometrically using the transmission and scanning electron microscopes. Grossly and microscopically, the bushbaby lung was found to be essentially similar to that of the other primates and the mammals in general. Subtle morphometric differences were, however, observed, with the bushbaby lung being generally structurally less sophisticated than that of the other primates on which comparable data are available, except for man. The weight-specific surface area of the blood-gas (tissue) barrier in G. senegalensis was 25 cm² g^-1. The thickness of the blood-gas barrier was 0.355 μm and the weight specific total anatomical pulmonary diffusing capacity 0.045 mlO₂ sec^-1 mbar¹ kg^-1. The morphological similarity of the galago lung to that of man gives sufficient grounds to justify its possible use in human pulmonary studies but caution has been called for in the general utilisation of primate tissues without first establishing their morphological characteristics, just because the primates are taken to be evolutionally close to man. The dearth of morphological studies on the various organ systems of the prosimians is pointed out.